Technical Field
The present invention relates to a target detection apparatus which detects a target positioned ahead of a vehicle by using a plurality of sensors.
Related Art
Conventionally, a technique is known which is for detecting a target existing in the area around a vehicle (for example, refer to JP-A-2001-99930). According to this technique, data obtained from a plurality of sensors are combined to correct information which is poor for individual data, thereby calculating a precise position of the detected target.
The target detection apparatus disclosed in JP-A-2001-99930 detects a target by using a millimeter wave radar and an image sensor. Regarding the target existing in a predetermined area, information on the target is generated based on information obtained from both the sensors.
According to the technique disclosed in JP-A-2001-99930, when the target detected in an overlapping detection area of both the sensors deviate from the overlapping detection area, the detected target is tracked. When tracking the detected target, if the target has moved to an area where the target can be detected by only one of the sensors, the reliability degree of data of the sensor is temporarily lowered. This is because using one of the sensors may detect an object such as a road surface and a small object, which may have no height sufficient to strike against the own vehicle. Note that, hereinafter, a target represents an object having a height sufficient to strike against the vehicle.
However, in such a situation where a target has moved to an area where the target can be detected by only one of the sensors, it is not preferable that a target reliability degree indicating probability that a target exists is lowered. This is because, even though the control has to be performed whose part of conditions for performing the control (control performance conditions) is that the target reliability degree is higher, the control may not be performed.
For example, if a target, such as a pedestrian, exists in an area which is proximate to and ahead of the own vehicle and in which only one of the sensors can detect the target, the control which should be normally performed, such as automatic control, may not be performed.